Lubricant and method of making



Patented May 6, 1947 LUBRICANT AND METHOD OF MAKING SAME John S. Yule, Chicago, and Barry L. Moir, Skokie,

111., assignors to The Pure Oil Company, Chicago, 111., a corporation of Ohio No Drawing. Application August 21, 1942,

Serial No. 455,612

7 Claims. 1

This invention relates to a lubricant and to the method of preparing the same. More particularly the invention is concerned with an extreme pressure lubricant suitable for lubricating hypoid gears and other metal bearing surfaces which are subjected to high pressures.

In Patents Nos. 2,211,231 and 2,211,306 there are disclosed lubricants and method of preparing same suitable for use under extreme pressure conditions. Although lubricants prepared in accordance with these patents have been found to give excellent service in commercial use, they do not show up particularly well on the S. A. E. load test.

The object of this invention is to improve lubricants of the type disclosed in the aforesaid atents whereby they will meet the S. A. E. test, and to make them suitable for use under heavy duty conditions, as for example in' the differentials and transmissions of heavy trucks and tanks.

Although various fatty bodies-may be sulfurized and then phosphorized in the manner set forth in the aforesaid patents, we prefer to prepare our novel lubricant by sulfurizing lard oil in the presence of a small amount of mineral oil and sulfur chloride and then phosphorizing the sulfurized product with phosphorus-sesquisulfide. The fatty body is sulfurized with approximately 5 to 9% by weight of sulfur at a temperature not in excess of 340 F. until the product gives a good copper strip corrosion test, and the sulfurized fatty body is phosphorized, at a temperature approaching but not in excess of 230 F. with phosphorus-sesquisulfide in an amount such that the finished product contains between 0.2 and 0.6% by weight of phosphorus until the product does not fume when heated above 230 F. The sulfurized and phosphorized lard oil is then cooked with sulfur under such conditions that the sulfur remains active but will not crystallize out on cooling. The resulting product when blended with mineral oil possesses the required characteristics.

As a specific example, a Gulf Coast lubricating oil having the following characteristics:

Gravity,A. RI 21/22 Flash point, F 350/360 Fire point, F 385/395 Vis. S. U. 100 F 200/210 Vis. S. U. 130 F 100/110 Vis. S. U. 210 F 43/45 Pour point F 20/-25 Color, N. P. A 2/3 Carbon residue, per cent .035 Demulsibility 180 F 1620 was mixed with sulfur chloride in the roportions of 5 parts by weight of oil to 0.5 of a part by weight of sulfur chloride. The mixture was then run into 87.1 parts by weight of prime lard oil and the lard oil was vigorously agitated during the addition thereto of the sulfur chloride-oil mixture. The entire mixture was then slowly heated to a temperature of approximately 270 F. and 7.4 parts by weight of finely ground flowers of sulfur were added over a period of about 10 minutes. After the addition of the sulfur the temperature of the mixture was raised to approximately 330 F. and held at this temperature until a copper stripimmersed therein for a period of 3 minutes showed no black coating. After heating for a period of approximately 7 hours at a temperature of from 330 to 340 F., the corrosion test was satisfactory. The mixture was continuously agitated during the entire period of heating. The mixture was then cooled rapidly to approximately F. and then permitted to cool slowly to room temperature. The resulting product had a viscosity of from 400 to 500 seconds Saybolt at 210 F.

99.6 parts of the sulfurized base thus prepared were mixed with 0.4 of a part of finely divided phosphorus sesqui-sulfide and heat applied to the mixture while it was continuously agitated. The temperature was raised to approximately 220 F. but not in excess of 230 F. The mixture was heated while being agitated for a period of approximately 5 hours and then allowed to cool.

The resulting sulfurized phosphorized base was then mixed with 5 per cent by weight of flowers of sulfur and the mixture was cooked with constant stirring for 6 hours at 285 F. and then allowed to cool.

It is to be understood that the invention is not limited to the specific conditions recited in the foregoing example. For example in the last step of cooking the sulfurized-phosphorized fatty material with sulfur, the amount of sulfur used may range from 2 to 8 per cent based on the sulfurizedphosphorized fatty material. The temperature at which the cooking is effected may range from approximately 270-300 F. and the time of cooking may range from approximately 2 to 6 hours. The lower percentages of sulfur require less time for cooking and do not give as high S. A. E. tests as the higher percentages. On the other hand sulfur in excess of 8 per cent results in separation of sulfur upon cooling unless the product is cooked for an excessive period of time. If the cooking is excessive the sulfur is tightly bound in stable chemical combination with the result that it is not in active form and the S. A. E. load test is low. Moreover, excessive cooking causes the 3 product to become too viscous to be handled satisfactorily. Cooking must be continued for a sumcient length of time so that sulfur does not separate from the resulting product when it is cooled to normal temperature. We have found, for example, that when 5 per cent of sulfur is used in preparation of the final product from the sulfur-phosphorus fatty base and the mixture is cooked for only approximately 2 hours the resulting product will not precipitate sulfur immediately but upon prolonged standing, will crystallize out sulfur. However, if the product is immediately blended with a major portion of mineral oil to make the final lubricant the sulfur does not crystallize out. On the other hand if cooking is carried out for approximately 6 hours the resulting base will not crystalliz out sulfur upon standing over long periods of time. Moreover, the longer period of cooking produces a product which is less corrosive and therefore causes lower tooth wear when tested on the Falex machine. Moreover, the longer period of cooking raises the temperature of activation of the sulfur and therefore permits operation of the hearing or gear surfaces in connection with which the lubricant is used at higher temperatures without experiencing excessive wear. Although the S. A. E. test on the base cooked for a shorter period is somewhat higher than the test on the base cooked for the longer period the S. A. E. test in both cases is above the required minimum, namely, approximately 300 pounds at 1000B. P. M. The sulfurized-phosphorized fatty oil base prepared in accordance with.Patents 2,211,306 and 2,211,231 will carry a load of only 90-100 pounds on the S. A. E. machine when blended in amounts of 18 per cent by weight of base to 82 per cent by weight of oil. a

A number of tests weremade on lubricants prepared in accordance with this invention and these were compared with commercial E. P. lubricants now on the market. The results on these tests are given in the following table:

From the table it is apparent that the lubricant prepared by adding 18 parts by weight of a base prepared in accordance with this invention and cooked for 6 hours, to 82 parts by weight of mineral oil was superior to all other lubricants in every respect except the S. A. E. load test and that as to this test the lubricant was above minimum requirements. For example, although on a comparable sulfur content basis commercial lubricant No. 4 carried a greater load than the lubricant in accordance with our invention, on the S. A. E. machine, the Falex wear test of our lubricant was far superior to that of commercial lubricant No. 4, and the temperature at which the torque suddenly rose and excessive wear took place was much higher.

The S. A. E. testing machine is well known and has been described in the literature. The Falex machine comprises two lever arms fulcrumed at one end. To the other end of each arm is rigidly fastened a block having a threaded bore, one being threaded right-handed and the other being threaded left-handed. One block is connected to a calibrated coil spring which in turn is connected to a dial type gauge for measuring load in pounds. A threaded screw having threads on each end corresponding to those of the blocks is screwed in the blocks. A ratchet wheel is fastened to the middle of the screw. The ratchet wheel is actuated by a pawl eccentrically operated so that a forward and backward movement is imparted thereto. Near the fulcrumed end of each lever arm and on the inner side thereof is rigidly mounted aself-aligning test block holder. Test specimens are held in these test block holders. A test shaft is adapted to be held vertically between the V-shaped jaws of the test block and is fastened to driving mechanism by means of a brass shearpin. The testspecimens are immersed in a bath of oil to be tested.

In starting the test the ratchet wheel is turned by hand until the test blocks are snug against the test shaft .The motor is then started and the S. A. E. Tests Falex Tooth Wear Test 800 Lbs.

P r t M t i'n lf" e cen ax. a w c Lubricant sulfur 3" 3 After After Alter Alter 8 co 0 e s. e rises at s R 1000 15 Min. 30 Min. Min. 60 Min. and i R. P. M. sive wear takes place 82% Mineral Oil and 18% 5-]? Base cooked with 5% 8 for 2 hrs. 5 F 2. 25 280 365 8 18 240 340 270-2) 82% Mineral Oil and 18% 8-? Base cooked with 5% s for 6 hrs. 2. 25 280 310 0 4 8 225 290-310 82% Mineral i] and 18% 8-? Base cooked-with 4% S for 2 hrs. 285 F 2.06 270 290 9 16 200 310 Commercial Lubricant #1.... 4. 00 240 550 120 421 lib-160 Commercial Lubricant #1 and 50% Mineral Oil 2. 00 210 220 300 424 lib-1B0 Commercial Lubricant #2.. 3. 220 550 120 275 120-176 Commercial Lubricant #3... 1. 60 220 300 392 904 Commercial Lubricant #4 2. 19 240 550 135 261 100-150 1 Gulf Coast Pale.

Viscosity Saybolt Universal at 100 F.200 seconds.

Where .the expression S-P base occurs in the foregoing table it is intended to mean sulfurizedphosphorized fatty body prepared in accordance with the specific example previously given. The mineral oil, used to make the blends with our base stock tested and reported in the table, was a mixture of Gulf Coast Pale oil having a Saybolt Universal viscosity of 2000 seconds at 100 F. and ,Gulf Coast Pale oil having a viscosity of 200 Saybolt Universal at 100 F., the two being blended with the base in such proportion as to give a final product having an S. A. A. viscosity of 90.

test specimens are automatically loaded by the pawl and ratchet wheel. The test is concluded 'brated in pound inches to measure the torque characteristics of the lubricant.

Thus, in accordance with our invention we have discovered a method of improving E. P. bases prepared in accordance with Patents 2,211,306 and 2,211,231 so that when blended with mineral oil the resulting lubricant has the ability to resist shock loads when used to lubricate hypoid gears. Moreover, the base when blended with mineral oil such as Gulf Coast neutral produces a cutting oil which is greatly superior to commercial cutting oils. When tested in tool cutting operations against one commercial brand of cutting oil, Iubnicant base prepared in accordance with our invention and blended with Gulf Coast neutral gave a tool life of approximately 150 per cent as great as the commercial cutting oil. When tested against several other well known commercial brands, cutting oil prepared with our base showed an increase in tool life of from 200-300 per cent.

Although in the foregoing table the various lubricants were made up by blending 18 per cent of the base with 82 per cent by weight of mineral oil the quantity of base used in the blend may vary over comparatively wide limits, depending on the viscosity and load carrying ability of the final blend desired; We have found, however, that a blend containing from 10 to 25 per cent of the base will give satisfactory all around performance.

We claim:

1. Th method of preparing a lubricant comprising cooking sulfurized and phosphorized fatty material, prepared by reacting fatty material with to 9% by weight of sulfur at temperatures not in excess of 340 F. until the product gives a good copper strip corrosion test, and then reacting the sulfurized material with suilicient phosphorussesquisulflde to incorporate therein between 0.2 and 0.6% by weight of phosphorus at a temperature approaching but not in excess of 230 F., with from about 2 to 8% by weight of sulfur at a temperature of approximately 270-300 F. and for a period of time, between about 2 and 6 hours, sumcient to cause the sulfur to become incorporated in the product in a loosely bound form in which it will not separate from the product upon cooling to atmospheric temperatures.

2. Method in accordance with claim 1 in which the fatty material is lard oil.

3. The method of preparing a lubricant which comprises cooking fatty oil, which has been sulfurized to good corrosion and then phosphorized with phosphorus sesquisulfide with from 2 to 8 per cent of sulfur for approximately 2 to 6 hours at a temperature of approximately 285 F.

4. The method of preparing a lubricant which comprises reacting fatty oil and approximately 5 to 9 per cent by weight of sulfur at a temperature approaching but not in excess of 340 F. until the product gives a good copper strip corrosion test,

reacting the sulfurized fatty oil with phosphorus sesquisulfide in such amount that the resultin product contains between 0.2 and 0.6 per cent by weight of phosphorus at a temperature approaching but not in excess of 230 F. until the product does not fume when heated above 230 F. and cooking the resulting product with 2 to 8 per cent of sulfur by weight at a temperature of 270-300 F. for a period of 2 to 6 hours.

5. A lubricant made in accordance with claim 1 having sulfur and phosphorus in stable combination with fatty material and containing sulfur in loose combination therewith, said lubricant having high load carrying ability and exhibiting low corrosion at normal operating gear temperatures in automotive equipment.

6. A lubricant made in accordance with claim 3 having sulfur and phosphorus in stable combination with fatty material and containing sulfur in loose combination therewith, said lubricant having high load carrying ability and exhibitin low corrosion at normal operating gear temperatures in automotive equipment.

'7. A lubricant made in accordance with claim 4 having sulfur and phosphorus in stable combination with fatty material and containing sulfur in loose combination therewith, said lubricant having high load carrying ability and exhibiting low corrosion at normal operating gear temperatures in automotive equipment.

JOHN S. YULE. HARRY L. MOIR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PA'I'E'NTS 

